A Regularized Active-Set method For Sparse Convex Quadratic Programming
Author:
Publisher: Stanford University
Published:
Total Pages: 128
ISBN-13:
DOWNLOAD EBOOKRead and Download eBook Full
Author:
Publisher: Stanford University
Published:
Total Pages: 128
ISBN-13:
DOWNLOAD EBOOKAuthor: Christopher Mario Maes
Publisher:
Published: 2010
Total Pages:
ISBN-13:
DOWNLOAD EBOOKAn active-set algorithm is developed for solving convex quadratic programs (QPs). The algorithm employs primal regularization within a bound-constrained augmented Lagrangian method. This leads to a sequence of QP subproblems that are feasible and strictly convex, and whose KKT systems are guaranteed to be nonsingular for any active set. A simplified, single-phase algorithm becomes possible for each QP subproblem. There is no need to control the inertia of the KKT system defining each search direction, and a simple step-length procedure may be used without risk of cycling in the presence of degeneracy. Since all KKT systems are nonsingular, they can be factored with a variety of sparse direct linear solvers. Block-LU updates of the KKT factors allow for active-set changes. The principal benefit of primal and dual regularization is that warm starts are possible from any given active set. This is vital inside sequential quadratic programming (SQP) methods for nonlinear optimization, such as the SNOPT solver. The method provides a reliable approach to solving sparse generalized least-squares problems. Ordinary least-squares problems with Tikhonov regularization and bounds can be solved as a single QP subproblem. The algorithm is implemented as the QPBLUR solver (Matlab and Fortran 95 versions) and the Fortran version has been integrated into SNOPT. The performance of QPBLUR is evaluated on a test set of large convex QPs, and on the sequences of QPs arising from SNOPT's SQP method.
Author: Thomas Wick
Publisher: Walter de Gruyter GmbH & Co KG
Published: 2020-10-12
Total Pages: 358
ISBN-13: 3110497395
DOWNLOAD EBOOKThis monograph is centered on mathematical modeling, innovative numerical algorithms and adaptive concepts to deal with fracture phenomena in multiphysics. State-of-the-art phase-field fracture models are complemented with prototype explanations and rigorous numerical analysis. These developments are embedded into a carefully designed balance between scientific computing aspects and numerical modeling of nonstationary coupled variational inequality systems. Therein, a focus is on nonlinear solvers, goal-oriented error estimation, predictor-corrector adaptivity, and interface conditions. Engineering applications show the potential for tackling practical problems within the fields of solid mechanics, porous media, and fluidstructure interaction.
Author: Jon Lee
Publisher: Springer Science & Business Media
Published: 2011-12-02
Total Pages: 687
ISBN-13: 1461419271
DOWNLOAD EBOOKMany engineering, operations, and scientific applications include a mixture of discrete and continuous decision variables and nonlinear relationships involving the decision variables that have a pronounced effect on the set of feasible and optimal solutions. Mixed-integer nonlinear programming (MINLP) problems combine the numerical difficulties of handling nonlinear functions with the challenge of optimizing in the context of nonconvex functions and discrete variables. MINLP is one of the most flexible modeling paradigms available for optimization; but because its scope is so broad, in the most general cases it is hopelessly intractable. Nonetheless, an expanding body of researchers and practitioners — including chemical engineers, operations researchers, industrial engineers, mechanical engineers, economists, statisticians, computer scientists, operations managers, and mathematical programmers — are interested in solving large-scale MINLP instances.
Author: Stanford University. Systems Optimization Laboratory
Publisher:
Published: 1986
Total Pages: 80
ISBN-13:
DOWNLOAD EBOOKThis report describes a single-phase quadratic programming method, an active-set method which solves a sequence of equality-constraint quadratic programs.
Author: Stanford University. Systems Optimization Laboratory
Publisher:
Published: 1987
Total Pages: 34
ISBN-13:
DOWNLOAD EBOOKMoreover, improvements in efficiency derived from exploiting new parallel and vector computer architectures are immediately applicable. An obvious application of the method is in sequential quadratic programming methods for nonlinearly constrained optimization, which require solution of a sequence of closely related quadratic programming subproblems. We discuss some ways in which the known relationship between successive problems can be exploited."
Author: Ekaterina A. Kostina
Publisher:
Published: 2003
Total Pages: 20
ISBN-13:
DOWNLOAD EBOOKAuthor: Laurie Ann Hulbert
Publisher:
Published: 1990
Total Pages: 288
ISBN-13:
DOWNLOAD EBOOKAuthor: Cornell University. Dept. of Computer Science
Publisher:
Published: 1988
Total Pages: 36
ISBN-13:
DOWNLOAD EBOOKWe show how a direct active set method for solving definite and indefinite quadratic programs with simple bounds can be efficiently implemented for large sparse problems. All of the necessary factorizations can be carried out in a static data structure that is set up before the numeric computation begins. The space required for these factorizations is no larger than that required for a single sparse Cholesky factorization of a matrix with the same sparsity structure as the Hessian of the quadratic. We propose several improvements to this basic algorithm: a new way to find a search direction in the indefinite case that allows us to free more than one variable at a time and a new heuristic method for finding a starting point. These ideas are motivated by the two-norm trust region problem. Additionally, we also show how projection techniques can be used to add several constraints to the active set at each iteration. Our experimental results show that an algorithm with these improvements runs much faster than the basic algorithm for positive definite problems and finds local minima with lower function values for indefinite problems.
Author: Ke-Lin Du
Publisher: Springer Nature
Published: 2019-09-12
Total Pages: 988
ISBN-13: 1447174526
DOWNLOAD EBOOKThis book provides a broad yet detailed introduction to neural networks and machine learning in a statistical framework. A single, comprehensive resource for study and further research, it explores the major popular neural network models and statistical learning approaches with examples and exercises and allows readers to gain a practical working understanding of the content. This updated new edition presents recently published results and includes six new chapters that correspond to the recent advances in computational learning theory, sparse coding, deep learning, big data and cloud computing. Each chapter features state-of-the-art descriptions and significant research findings. The topics covered include: • multilayer perceptron; • the Hopfield network; • associative memory models;• clustering models and algorithms; • t he radial basis function network; • recurrent neural networks; • nonnegative matrix factorization; • independent component analysis; •probabilistic and Bayesian networks; and • fuzzy sets and logic. Focusing on the prominent accomplishments and their practical aspects, this book provides academic and technical staff, as well as graduate students and researchers with a solid foundation and comprehensive reference on the fields of neural networks, pattern recognition, signal processing, and machine learning.